Le 16.01.2009 20:04, Trevor G Quayle nous fit lire :
> Le_Forgeron <jgr### [at] freefr> wrote:

>> Solids are:
>>  1. Milk carton (berlingot) quartic
>>  2. Cone
>>  3. conocuneus (coin conique) quartic
>>  4. Sphere
>>  5. spherical top on cylinder
>>  6. Cylinder
> 
> #3 could also be replaced with a paraboloid.
> 
> V=1/2pi a^2 h    - a=R, h=2R
> V=1/2pi R^2 2R


> 
> -tgq
> 
Yes. Well seen.
Nevertheless, I have a slight preference for ruled surface when
possible. (1,2,3 & 6 are ruled surfaces, 4 is obvious, and the one I'm
most dissatisfied with is 5). That's personal, so no problem if your
favorite suite uses a paraboloid, it's just that recognizing x2 vs x4
only by the eye is not obvious for me, whereas a ruled surface is less
ambiguous.

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